The internalisation efficiency and cytotoxicity of polymeric microparticles and capsules were studied for three different adherent cell lines: HeLa (human cervice cancer), MCF-7 (human breast cancer) and B104 (murine neuroblastoma). Microparticles of colloidal CaCO3 cores coated with either layer-by-layer self-assembled oppositely charged biosynthetic (PSS\PAH) or biodegradable (DXS\PRM) polyelectrolytes and hollow capsules thereof, obtained upon removal of the CaCO3 cores by EDTA, were fabricated. Fluorescent-labeled polymer layers coated onto CaCO3 cores were employed for evaluating cell uptake efficiency. Confocal laser scanning microscopy was used to confirm dissolution of preformed biodegradable multilayers. Cellular viability for all type of colloidal entities was preserved, indicating safety and tolerability of the potential drug carriers.